A total of 174 specimens of the spined loach Cobitis taenia Linnaeus, 1758, comprising 117 females, 45 males and 12 juveniles, from Lake Klawoj (Poland) were identified as C. taenia from their karyotype (2n = 48 chromosomes). The overall sex ratio (M:F = 1:2.6) showed that females dominated in the population, but this varied with increasing fish size. Age and growth were determined based on otolith measurements. Standard lengths were back- calculated from the regression of fish standard length on the otolith radius and the growth pattern was described using the von Bertalanffy model separately for males and females, which revealed a strong fit for both females (Lt =92.4(1– exp(–0.278 (t – 0.456)); r2 = 0.803) and males (Lt=120.6(1 – exp(– 0.227 (t – 0.558); r2= 0.772). Comparison of asymptotic length with maximum observed size of males and females revealed that all values were a bit overestimated (as per the Taylor criteria). The SL – weight equations for males (W = 0.0003 SL3.8377; r2 = 0.8961) and females (W = 0.0039 SL3.1683; r2 = 0.9616) indicated allometric growth in both sexes, though more so in males than in females.
Male rats aged 45, 85, 145 and 270 days (daily body mass increments on ar, optimal diet containing casein were 6.73, 2.88, 0.53 and 0.31 g respectively) were fed 15 days ad libitum on a diet with a nutrient content physiological for their age, in which the protein source was milk casein (ratio of essential to nonessential amino acids E/N = 0.79, compensation coefficient K = 14) or wheat gluten (E/N = 0.30, K= -8). In the case of gluten, net protein utilization (NPU) fell markedly in rapidly growing animals aged 45 and 85 days (33 and 30 % more than with casein), indicating that without essential amino acid compensation, gluten is inadequate for animals of this age, whose organism requires fully ensured proteosynthesis for growth and development. In adolescence and adulthood (145 and 270 days), the utilization of proteins is not dependent on their quality (the decrease in NPU 13 and 12 % - is nonsignificant). That means that a smaller amount of essential amino acids, including the limiting amino acid in uncompensated protein, is sufficient for the maintenance and renewal of organs and tissues, i.e. for proteosynthesis. The activation of gluconeogenesis (phosphoenolpyruvate carboxvkinase activity in the liver) after the intake of plant protein confirms the effect of proteins on catabolic processes.
Age-dependent changes of the caecal fermentation pattern were studied in female chickens using in vitro batch incubation technique. Chickens were sequentially killed at the age of 1, 2, 3 and 4 months, their caecal contents added to a broth with starch and incubated at 39 °C for 20 h. Net productions of short-chain fatty acids (SCFA), succinate, ethanol, lactate, methane, hydrogen and ammonia were determined. Methanogenesis was absent in caeca of 1-month-old chickens. Production of methane started in the second month and doubled in the third month of age. The start of methanogenesis was accompanied by changes of the fermentation stoichiometry. The production of succinate ceased and that of ethanol decreased to less than one tenth. There were no major changes of the caecal fermentation pattern in the fourth month of age. The ammonia production increased in the second month, indicating increased deamination activity. No major shifts in SCFA molar composition dependent on age were found. Calculated hydrogen recoveries suggest a decrease of reductive acetogenesis until 3 months of age. It can thus be concluded that age and the onset of methane production affect the fermentation pattern in the caeca of chickens.
Postconditioning (PostC) is a re cently discovered phenomenon whereby brief repetitive cycles of ischaemia with intermittent reperfusion following prolonged is chaemia elicit cardioprotection. This study investigated whether the age, genetic characteristics or number of repetitive cycles influenced the protective effect of PostC in mice. C57BL/6 floxed or non-floxed STAT-3 mice aged between 14-16 weeks (young) or 18-20 weeks (older) were perfused on a Langendorff apparatus and subjected to 35 min global ischaemia and 45 min reperfusion. PostC was elicited by either 3 (PostC-3) or 6 cycles (PostC-6) of 10s ischaemia and 10 s reperfusion. PostC-3 and PostC-6 in both young and older non-floxed mice reduced the myocar dial infarct size. In contrast, only PostC-3 reduced myocardial infarct size in young floxed mice. Neither PostC-3 nor PostC-6 reduced the in farct in older floxed mice. Our data reveal that genetic characteristics, a minute difference in age or the nu mber of postconditioning cycles are critical factors to be consid ered for the successful effect of ischaemic postconditioning in a murine model. Moreover, these factors should be taken into consideration for future experimental research or clinical applications of this protective phenomenon., S. J. Somers ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy
Several aspects of growth and feeding of C. paludica have been assessed in two different environments: a lenitic and a lotic hydrosystem, Portil lagoon and Rivera de Cala river respectively. Growth patterns showed some differences with Iberian loach growing slower in the lagoon than in the river. Because of this, although individuals of both populations reach sexual maturity in their second year (year-class 1+), specimens of lagoon population mature at smaller sizes. The C. paludica population in the river showed a better somatic condition than in the lagoon. In both hydrosystems, their diet was mainly chironomid larvae and ostracods, although the Portil lagoon Iberian loach population showed a clear trophic segregation between young of the year (year-class 0+) and sexually matures individuals (year-class ≥ 1+).
Metaschistura cristata is a small nemacheilid loach species found at a few localities only in Turkmenistan and Iran. The present study reports, for the first time, data on its biology, based on 747 specimens collected from the River Zanglanlou in north-eastern Iran. Specimens were collected at monthly intervals over two reproductive seasons from February to June 2007 and 2008. Maximum age, based on opercula readings, was 4+ years for both sexes. Specimens ranged in size from 25 to 87 mm total length and weighed from 0.09 to 4.91 g. Length-weight relationships implied positive allometric growth for both sexes and the sex ratio was 1 : 1.2 in favour of females. The Gonadosomatic indicated that peak reproduction occurred during April and May, with highest average values of 1.473 ± 0.99 for males and 12.9 ± 7.14 for females in April. Oocyte diameter ranged from 0.53 to 1.46 mm, with a mean value of 0.943 mm. Absolute and relative fecundity ranged between 114-1246 eggs and 79.47-1285.71 eggs/g, respectively. Absolute fecundity and oocyte diameter to fish size (length and weight) were directly correlated, while the relationship between relative fecundity and fish size (length and weight) showed an inverse power function.
GABA exhibits depolarizing action in the immature neurons due to high intracellular activity of chloride ions. It is maintained by cation-chloride cotransporter NKCC1 which is present in immature brain. Bumetanide is a specific inhibitor of this cotransporter. We studied possible anticonvulsant activity of bumetanide in pentyl enetetrazol-induced seizures in three age groups of rat pups (7, 12, and 18 days old). Pretreatment with bumetanide (0.2-1 mg/kg i.p.) resulted in dose-dependent decrease of incidence of the tonic phase of generalized tonic-clonic seizures in 12-day-old rats only. No effect was observed in younger and older animals. Higher dose of bumetanide (2.5 mg/kg) did not affect tonic convulsions but, on the contrary, decreased latencies of generalized seizures in 12-day-old animals. Lack of marked anticonvulsant effect is probably due to relative maturity of neurons in the brainstem where the generator of generalized seizures is localized. Age- and dose-specific suppression of the tonic phase needs further analysis. and Obsahuje seznam literatury
Altered Ca2+ handling may be responsible for the development of cardiac contractile dysfunctions with advanced age. In the present study, we investigated the roles of oxidative damage to sarcoplasmic reticulum (SR) and expression of Ca2+-ATPase (SERCA 2a) and phospholamban in age-associated dysfunction of cardiac SR. SR vesicles were prepared from hearts of 2-, 6-, 15-, and 26-month-old Wistar rats. Although activity of Ca2+-ATPase decreased with advancing age, no differences in relative amounts of SERCA 2a and phospholamban protein were observed. On the other hand, significant accumulation of protein oxidative damage occurred with aging. The results of this study suggest that agerelated alteration in Ca2+-ATPase activity in the rat heart is not a consequence of decreased protein levels of SERCA 2a and phospholamban, but could arise from oxidative modifications of SR proteins. Cellular oxidative damage caused by reactive oxygen species could contribute to age-related alternations in myocardial relaxation., E. Babušíková ... [et al.]., and Obsahuje seznam literatury
Age-associated changes in large blood vessels were characterized by increased arterial wall thickness, luminal dilation and impaired endothelial function. But little is known about the effect of age on structural and functional changes in small resistance arteries. The mechanisms underlying age-associated endothelial dysfunction in rat mesenteric resistance arteries were investigated in the present study. Small rat mesenteric arteries were excised and cannulated, and vascular endothelial functions were tested by acetylcholine (ACh). Our experiments showed (1) endotheliumdependent vasorelaxation induced by ACh was reduced in aged mesenteric arteries; (2) blockade of Kca channels markedly reduced the vasodilation in young and adult rats, the resultant reduction in aged rats was much smaller compared with young and adult rats; (3) inhibition of endothelial nitric oxide synthase (NOS) resulted in a significant reduction of vasodilation in young and adult, but there was a smaller reduction in aged rats. The results suggest that (1) endothelial function was impaired in mesenteric arteries of aged rats; (2) both Kca channels and nitric oxide (NO) contribute together to the ACh-induced vasorelaxation in small mesenteric arteries, and (3) both the impairment of Kca channel function and decreased NO account for the age-related endothelial dysfunction., E. Zhou, D. Qing, J. Li., and Obsahuje bibliografii a bibliografické odkazy